Every religious community, just as is the case in any human community, has a some conception and system of authority. Even the loosest association of believers shares an idea and ideal of what qualifies an authority, what the standards are for some decision to be authoritative, and what circumstances might allow for one to disobey an authority.
So why does the nature and structure of religious authority matter? Religious authority is, in many fundamental ways, an important source of cohesion, stability, and continuity within religious communities. Normally we think of such communities as being bound together by a shared understanding of that which is considered sacred, transcendent, and moral, yet thats not all there is to it.
In all of these communities there are those who are seen to have the power to structure the sacred, to transmit the transcendent, and to interpret the moral. These activities create cohesion and stability as much as or more than anything else. Whether few or many in number, these individuals constitute the religious authority for the community.
Through them, that which does bond the community is given structure, meaning, and interpretation. Without them, the ties that bind would fragment and the members would be torn apart by the social forces brought to bear upon them by other communities and other authorities.
It should not be assumed, however, that the structures created by a system of religious authority are somehow imposed upon a community by authority figures. Genuine authority requires legitimacy and that, in turn, is defined through social norms and standards that are created by the group itself. There is thus no legitimacy and hence no true authority that is not actively acknowledged and created by the faith community itself.
As a consequence, the nature and structure of religious authority provide important insights into the nature and structure of both religious communities and religious belief systems. All of these are both a reflection of and influence upon the others, creating a never-ending feedback loop that slowly changes over time.
Religious authorities help define the boundaries of belief and behavior that provide structure to the community, but the legitimacy to do such things is created by the acquiescence of the communitys members and that, of course, depends upon their agreement that the boundaries on belief and behavior are just and acceptable.
This is of course one of the reasons that any problems with a religious groups standards cannot be laid solely at the feet of those authorities who are charged with developing and applying the standards. The communitys members who have agreed to accept the legitimacy of the authority of their religious leaders must shoulder some of the responsibility as well. They are not passive observers; rather, it is they who create the conditions in which religious authority can act both for good and for ill.